Hydraulic controlling device for machine-tools.



F. WOLFENSBERGER.

HYDRAULIC CONTROILLING DEVICE FOR MACHINE TOOLS.

APPLICATION FILED 050.12. 1913.

L m fiwe Patented July 10, 1917.

3 SHEETS-SHEET I- F. WOLFENSBERGER.

HYDRAULIC CONTROLLING DEVICE FOR MACHINE TOOLS.

APPLICATION FILED DEC. 12, 1913.

Patented July 10, 191?.

3 SHEETS-SHEET 2- In I //V VIEW/70R T/VEGSEKS;

M W M W F. WOLFENSBERGER. HYDRAULIC CONTROLLING DEVICE FOR MACHINETOOLS.

APPLICATION FILED DEC.12, I913.

Patented. July 10, 1917.

3 SHEETSSHEET 3- anon-o0 lie W/T/VEJJfS:

an n

HYDRAULIC CONTROLLING DEVICE FOR MACHINE-TOOLS. I

Specification of Letters Patent.

Patented July llll, 191?.

Application filed December 12, 1913. Serial No. 806,158.

To all'whom it may concern:

Be it known that I, FRITZ WOLFENSBERGER, a subject of the GermanEmperor, residing at Mulheim-on-the-Rhine, Germany, Deut -zerstrasse,have invented new and useful Improvements in Hydraulic ControllingDevices for'Machine-Tools, of which the following is a specification.

This invention relates to an improved hydraulically operated toolmachine. The feed is automatically efl ected by hydrostatic pressureafter the machine is once started, so that an absolutely determinedcontrol of the speed which has been previously exactly adjusted, iseffected, and the operation of the feeding mechanism is renderedindependent from frictional conditions and the head of the hydrostaticpressure; and the machine is brought to a standstill after havingperformed a predetermined amount of work.

The movement of the tools, according to this invention, is effected byattaching on the tool machine a hydraulic cylinder and connecting thetool with a piston or vice versa, the .1 piston sliding in this cylinderby the pressure of water entering the cylinder from a pump withoutaccumulator.

The omission of an accumulator in the conduit between pump and operatingcylinder is rendered necessary for the reason that thereby a positiverelation between the stroke of the pump and the movement of the tool isobtained, in the sense that the volume of water displaced by each strokeof the pump effects a proportionate and accurately predetermined advanceof the piston of the operating cylinder, regardless of the resistance ofthe tool that is connected with the operating piston and independentfrom the friction of the machine.

The controlling device is based upon the idea that in a hydraulic systemwithout an accumulator which consists merely of a conduit, an activemechanically driven pump piston and a passive Working piston, thepressure in the conduit is solely determined by the elastic resistanceof the passive piston and that the pressure suddenly rises as soon asthe piston encounters a rigid resistance. Th senoountering a resistanceand the increasing of pressure in the conduit thereby entailed, isutilized in accordance with the present invention for actuating certaincontrol member or members combined with hydraulic valves which initiateanother tool movement.

A valve that connects the cylinder with the waste water is primarilyopened by a control member, so that the cylinder or piston is allowed tobe drawn back by a suit able constantly operating force which may hespring tension, and thus the tool is returned to its inoperativeposition.

Even though, for the above cited reasons, the operating cylinder duringthe time that the tool is working must be connected with a pump notprovided with an accumulator, nevertheless said cylinder may, during theperiod that it approaches the work, be connected with a source of liquidsupply provided With an accumulator, because an accurately determinedrate of feed is not required during that period, but only the quickestpossible advance of the tool to the work, which may be produced by auniform hydraulic pressure that is less than that which is required inthe pump without accumulator during the cutting operation. Thisaccumulator is in no way dependent on the pump without an accumulatorrequired for feeding the tool during the cutting operation; the feedcould of course be effected by this pump, but it is advantageouslyeffected by another pump adapted to operate at high pressure, while thepump with accumulator operates preferably at a low pressure. As soon asthe tool, subject to the pressure of the accumulator water and makingrapid progress, has approached near enough to the work, the cylindermust be disconnected from the accumulator and must be arranged to beactuated only by the high pressure pump without accumulator, in order toefiect the slow but accurately regulated cutting movement of the tool.

Special means are necessary when it is desired to render a plurality oftools simultancously operative by hydraulic means from a. centralstation in such a manner that so long as they are separated from theWorlr they move quickly, while, when they have encountered the work,they are fed automatically by a hydraulic high pressure pump at a ratedetermined by the stroke of the ump.

This problem presents itself, for example, in the case of amulti-spindle drilling machine: Each drill must be provided with a.separate hydraulic cylinder and a special hydraulic high pressure pump,in order to effect the feed of each drill separately. Each drill must beprovided wit-l1 a. separate con trol member causing the tool to returnat the right time, as all have to effect strokes of different length andperform their work at different times.

Figure 1 is an elevation partly in section, of a multi-spindle drillingmachine showing displaced from its normal position and on a larger scalea pump H Fig. 2 is a plan of the same;

Fig. 3 is a diagrammatic illustration showing the connections of thevarious control members;

Figs. 4* and 4 are details; 4" being in section, and 4 in plan, showingparticular features of the control of two valves;

Fig. 5 is an enlarged view in section of the valve-box of the centralstation and of a single valve-box appurtenant to a drill;

Fig. 6 is a modification of the non-return valve shown in Fig. 5; and,

Fig. 6 is a detail of the spring 0 of Fig. 6.

Similar reference characters in these figures refer to correspondingparts.

The machine illustrated by way of example contains a plurality of drillsd (Z (Z (Z 03 which are connected with hydraulic cylinders I, II, III,IV, V by having the spindles and the cylinders provided with racks, eachpair of which engage a common toothed wheel or pinion a, so thatcylinder and spindle are compelled to move in opposite directions. Eachcylinder is connected to a high pressure pump H H which is without anaccumulator; all these pumps are constantly actuated by suitable means,such as a belt C, driven from the machine. The stationary pistons h b ofthe cylinders are secured to the frame of the tool I machine. Avalve-box k 70 (Figs. 2, 3 and 5) is appurtenant to each drill, thevalves thereof being connected in the manner shown in Fig. 3, with thehigh pressure pump H of the respective drill, with the waste waterconduit A from which the suction inlet of the high pressure pump is fedand with the conduits x m which connect with the central station throughthe joint conduit :12. Separated from these valve-boxes 7v is there isarranged at a suitable point the central station with a valve-box k(Figs. 2, 3 and 5), which is connected with the hydraulic accumulator Nand in addition communicates with the said joint conduit a": for all thevalve-boxes of the drills. The valve-box ic is further in communicationwith one of the valveboxes k is, for instance is, by means of a conduit11 The valve-boxes 70 k is, k, k of the drills (Figs. 3 and 5) eachcontain four lives P1, 917 1' 9 92, 1 7 2 7 Q31 32*, 9*, 1, s and 19 91' 8 and are connected with starting cylinders g g 9 g and g hereinafterdescribed, which bring some of the valves into their initial positions.All these starting cylinders are in communication by means of theconduit m, with the valve chamber of the box k containing the valves m,n. The valves s s s 8* and s are joined by conduits 2 2 2 2. and 2 andnon-return valves 6 tat, t and t to the conduit w; and one of the valvess s s 8 and s (viz. s is in communication by a conduit y with the valve0 in the central valve-box 7a,.

The valves 9 r .5 s (Fig. 4 4:", 5) are pressed by springs on theirseats, but can be opened by spindles with left or right-hand threads.The spindles are connected by toothed wheels 0 (Fig. 4*, 4), so that byturning the spindle s s the other spindles r .7 are also turned, but 1nthe opposite direction. The spindles are provided with springs, 0 (Fig.4), tending to turn these spindles to occupy certain normal positions,a". e., to open valves 7 r and to close valve 8 8 By turning levers suchas a (Fig. t") connected to the spindles of the valvesr 1', s 8 thesespindles move the valves to occupy the contrary position, so that'valvesr T will be closed and valves 8 8 opened. In this position the valvesare held by ratchet wheels and pawls o 42 (Figs. 3 and 5).

The valves g g normally are pressed on their seats by springs; (Figs. 3,5), but if the pressure in the respective cylinders exceeds the normalmeasure, the valves 9 will be raised, the liquid enters the space abovethe piston of thevalve and displaces the piston. These control membersor piston valves 9 g are so connected with thesaid valves 1' 1' 8 s asto reverse these latter valves, thus causing the entrance or outlet ofwater to the cylinders and initiating new piston movements. Pistonvalves g 9 when displaced, strike pawls o 'v and these are moved out ofengagement with their ratchet wheels so that valves r r 8 8 under theinfluence of the springs 0 return to their normal positions.

The initial adjustment of the valves 1' r 8 s is regulated by thestarting cylinders g g. The pistons of these cylinders are forced intothe interior of the cylinder by a force such as spring tension (Figs. 2and 5). When, however, water is fed through the central station andconduit as from the accumulator N, then the pistons are forced out andremain in that outer po sition until the conduit w is again placed incommunication with the Waste water conduit A, due to changes in thepositions of the valves of the central station whereupon the saidpistons return to their interior position as illustrated. The startingcylin der pistons are connected with the levers e 6 (see 0 Figs. 4. and49) of the valves 7' r 8 s in such a manner that upon the forwardmovement of the pistons the valves are moved from out of their nor- 'malor final position into their illustrated initial position, (Fig. 3) inwhich valvesr r are closed and s s are opened. The valves however arenot so connected with the pistons of the starting cylinders that theyare forced to accompany the pistons on the return movement of thelatter. Inasmuch as the connection is effected by such means as a forkedlever E (Fig. 4. the valves remain retarded in their position by theratchets o '0 when the pistons return.

The valves m and n of the central station, joined to one another 'bygears b are brought into their initial position by a hand lever f andheld in this position by a pawl '11.

This pawl may be released by the piston valve 0, when the same isdisplaced upon the increase in pressure in the conduit 3 the valves m nsubsequently return into their normal or final position (we closed, oropened).

The operation is as follows:

For starting the engine from the central station the lever f is broughtin such a position that (as indicated in Fig. 3) valve m is open andvalve 7% closed. Then water flows from the accumulator through the valvem and by conduit 00 to the several starting cylinders g g 9 g and 9 Thepistons of the starting cylinders move forward and turn the spindles ofthe valves 1' 8 W, 8 W, 8, r 8 and r 8 so that r r r, r, r are closedand s s s s, s are opened (Fig.

By this means the cylinders I, II, III, IV and V of the several drillsare placed in communication with the conduit w and, therefore, with theaccumulator. Furthermore, each of the cylinders, as before explained, isconnected with a high pressure pump II ll. (Fig. 3). As the resistanceto the movement of the drill before it reaches the work is considerablyless than the available accumulator pressure, the drill proceeds underthe ressure of the accumulator water with w llCll the Water supplied bythe high pressure pump mingles, until the work is reached. Then theresistance increasesto such an extent that it cannot be overcome by theaccumulator pressure. As

nected by a pipe 3 with one of the cylinders-the cylider V foreXample,(Figs. 2

and 3 show). Accordingly as soon as the cylinder has completed its work,and its pressure lncreases owing to encountering a stop (such as i inFig. 3), the piston valve 0 opens and the valves m and n are reversed.The result is that the conduit x is brought in communication with thewaste water chamber and so relieved; and all the pistons of the startingcylinders g g 9 g and 9 return to the1r end position, shown in thedrawings, while the valves 7', r W, T and r and s s 8 a and s actuatedby them, are in the meantime held in position by the pawls '0 '0 e '0and '0 When the pressure in the cylinder V increases further, pistonvalve 9 is also opened and the two valves r and s reversed so as to openr and close .9 By this means the cylinder V is brought in communicationwith the waste water chamber and so relieved and the drill spindle canmove retractively under the infiuence of a counter pressure such as the.weight of the cylinder. The same operation is repeated in the othercylinders, as soon as they have finished their work and their pistonsstrike a stop which causes the pressure to riseand the valve 9 y of therespective cylinders to open. The cylinders I, II IV are not connectedwith the valve 0 of the central station like the cylinder V. This isnotnecessary, because if the valves g f, g and 9 open later than 9", theaction is the same as described with reference to cylinder'V; if,however, one valve, the valve 9 for example, opens earlier, al-

though the pawl o is displaced, whereby the blocking of the valves 7'and s ceases, the valves are unable to spring back, as they areheld'inposition by the start-in cylinder pistons. In this case the pump TI? ofthe valve in question continues to pump idly, an excessive increase ofpressure in theconduit being prevented by the safety valve As soon asthe cylinder V has reached its stop, however, and back pressure upon thevalves Q5 has caused the reversal of the valves m and n as well as thevalves 1' and s, the starting cylinder pistons also move retractivelyand the valves r and s are then able to spring back under the influenceof the valve springs, whereby the cylinder III is relieved.

The operation will be apparent 'by the following table, relatingvto clinder V for example indicating the positlons of the valves 15 asfollows:

() valve closes.

valve closed. (1) valve opens.

1 valve open.

Positions of the valves.

Functions of the hydraulic control. Action upon the piston.

m n o g r .9

At the central station lever f is hand operated. (l) 1 Piston oi thestarting cylinder 9 moves forward.

Valve 1n places the startlng cylinder g m comma: nication with apressure water accumulator.

The starting cylinder 9 has reached its extreme 1 (1) Cylinder V movesquickly forward.

position. S rings of valves 1 and a cooked, valves r an .9 brought intheir initial position. (Fig. 3.)

The tool strikes the work piece. The pressure of 1 1 Cylinder V movesslowly forward.

the accumulator is insufficient for further forward movement. Thenon-return valve t closed. The hressure in the cylinder rises throughthe pump The stop 1' of cylinder V is reached. 1 1 The cyglinder Vremains stationary (under pressure The pressure rises until it opens thepiston valve 0; (1) (1) 1 The cylinder V remains stationary (without thevalves m, n are reversed. hydraulic pressure). The piston oi the startmgeyhnder g tends to move retractively.

The pressure in cylinder V continues to rise until it 1 (l) (1) Thecylinder V recedes. End of operation. opians the reversing valve 4 andthis reverses the va ves r 6?.

The advantages of such a hydraulic reversible multispindle drillingmachine resides in greateconomy in labor. Asshming that as much time isoccupied in unclamping a piece of work and clamping a fresh piece as isrequired for machining a piece, such a machine replaces six separatemachines which would require attention by six workmen, because after allthe five drilling tools (drill, cutter, reamer, tap and so forth) havecompleted their work, it is only necessary to rotate the table through60 from a central station and by reversing the lever f to supply waterunder pressure to the several starting cylinders, -whereupon theycomplete their work independently of each other, while the workmanunclamps the finished piece of work and clamps a fresh blank. As eachblank is machined by five difierent tools in succession, thiscorresponds to machining by five separate machines whose output in agiven time would only amount to five-sixths of the out-put of thehydraulic machine as they are inoperative during the clamping andunclamping operations.

Fig. 6 shows a modification of the valve t (Fig. 5) in the conduit 2leading to the valve 8 This valve has for its purpose to close thesupply of accumulator water to the work cylinder of the drill when thedrill has reached the work, the supply of the high pressure pump H beingcontinued.

Instead of building this valve 25 as a nonreturn valve (as illustratedin Fig. 5) in certain cases it is preferred to govern the valve by theforwardly moving piston or cylinder which drives the tool. The rod u(Fig. 6) with the adjustable tappet Z is attached to the cylinder Vmoving upward under the influence of the accumulator water. Onapproaching the work piece this tappet displaces by the rod i the leverw, thereby releasing the spring 0 (Figs. 6 and 6 and reversing the valve25 so as to close it. The cylinder is then in communication only withthe high pressure pump H and the tool is displaced toward the work piecewith a feed movement corresponding to the stroke of the pump.

I claim:

1. Hydraulic controlling device for machine tools, consisting of thecombination of a tool machine, a tool, hydraulic cylinder and piston,one of said hydraulic members being attached to said machine and theother member'being connected with said tool, a-con raeaeeo stantlydriven high pressure fluid pump without accumulator, a conduit betweensaid pump and said cylinder, a stop to limit the movement of said pistonor cylinder whereby an excess of pressure is caused in said conduit, aloaded piston valve in connection With said conduit, said piston valvebeing adapted to be displaced by the excess of pressure in said conduit,a waste fluid chamber, and a valve released by said piston valve, whichvalve on the displacement of said piston valve opens a connection fromsaid cylinder to said waste fluid chamber permitting said piston orcylinder to return.

2. Hydraulic controlling device for machine tools, consisting of thecombination of a tool machine, a tool, a hydraulic cylinder and piston,

being connected with said tool, a constantly driven high pressure fluidpump without accumulator, a conduit between said pump and said cylinder,a stop to limit the movement of said piston or cylinder whereby anexcess of pressure is caused in said conduit, a loaded piston valve inconnection with said conduit, said piston valve being adapted to bedisplaced by the excess of pressure in said conduit, a waste chamber, avalve separating said cylinder from said waste fluid chamber, means forholding said valve in one position, and means adapted to be released bysaid piston valve tending to move said valve to the'contrary position.

3. Hydraulic controlling device for machine tools, consisting of thecombination of a tool machine, a tool, hydraulic cylinder and piston,one of said hydraulic members being attached to said machine and theother member being connected with said tool, a constantly driven highpressure fluid pump without accumulator, a conduit between said pump andsaid cylinder, a stop to limit the movement of said piston or cylinderwhereby an excess of pressure is caused in said conduit, a loaded pistonvalve in connection with said conduit, said piston valve being adaptedto be displaced by the excess of pressure in said conduit, a waste fluidchamber, a valve controlled by said piston valve, which valve on thedisplacement of said piston valve opens a connection of said cylinder tosaid waste fluid chamber'so as to allow said piston or cylinder toreturn, another valve, and a fluid pressure starting cylinder with astarting piston moving therein and connected with said latter valve soas to hold same in one position when actuated by fluid pressure, meanstending to move said valve to the opposite position and a second pistonvalve in communication with said conduit and adapted for releasing saidmeans.

4. Hydraulic controlling device for machine tools, consisting of thecombination of one of said hydraulic members being attached to saidmachine and the other .tool so as to move same,

conduit, said piston valves a tool machine, a tool, hydraulic cylinderand piston, one of said hydraulic members being attached to said machineand the other member being coimected with said tool so as to move same,a constantly driven high pressure fluid pump without accumulator, aconduit between said pump and cylinder, an accumulator, a conduitbetween said cylinder and said accumulator-,a waste fluid chamber, avalve separatingsaid cylinder from said waste fluid chamber and a valvein the said conduit between cylinder and accumulator, these said valvesbeing so connected, that when one is closed the other is open.

5. Hydraulic controlling device for ma chine tools, consisting of thecombination of a tool machine, a tool, hydraulic working cylinder andpiston, one of said hydraulic members being attached to said machine andthe other member being connected with said a constantly driven hlghpressure fluid pump without accumulator, a conduit between said pump andsaid cylinder, an accumulator, a stop to limit the movement of saidpiston or cylinder whereby an excess of pressure in said conduit iscaused, a loaded piston valve in connection with said conduit, saidpiston valve being adapted to be displaced by the excess of pressure insaid conduit, a waste fluld chamber, a valve separating said cylinderfrom said waste fluid chamber, a valve separating the cylinder from saidaccumulater, an auxiliary fluid pressure starting cylinder, a startingpiston movable therein and connected with said valves so as to hold samein one position, means tending to move said valves to the contraryposition, said piston valve being means and permit operation thereof.

t3. Hydraulic controlling device for machine tools, consisting of thecombination of a tool machine, a tool, hydraulic cylinder and piston,one of said hydraulic members being attached to said machine and theother member being connected with said tool so as to move same, aconstantly driven high pressure fluid pump without accumulator, aconduit between said pump and said cylinder, a stop to limit themovement of said piston or cylinder whereby an excess of pressure insaid conduit is caused two loaded piston valves in connection with saidbeing adapted to be displaced by the excess of ressure in said conduit,a valve controlled y one of said piston valves, which valve on thedisplacement ofsaid latter piston valve opens an outlet from saidcylinder permitting-said plston or cylinder to return, another valve, afluid pressure starting cylinder, a starting plston movable therein andconnected with sald other valve so as tohold same in one position, meanstending to move said valve adapted to release said to the oppositeposition, said other piston valve being adapted on its displacement torelease said means.

7. Hydraulic controlling device for multiple machine tools consisting ofthe combination of a tool machine, a plurality of tools, a plurality ofhydraulic Working cylinders and pistons, certain of said hydraullcmembers being connected with one of said tools so as to move it, saidother hydraulic members being attached on the machine, a

waste fluid chamber, a plurality of valves which connect the cylinderswith said Waste chamber, a plurality of other; valves which connect thecylinders with an accumulator, a plurality of starting cylinders adaptedto move said valves, a central. station valve-box having a valve foradmitting fluid under pressure to the starting cylinders so as to causesaid valves between the working cylinders and the waste fluid chamber toclose, and said valves between the working cylinders and the accumulatorto open, means for closin the communication of the working cylind ersand the accumulator at a predetermined moment, a plurality of highpressure pumps, a central station piston valve adapted to be displacedby an excess of pressure produced by one of said hydraulic pumps, saidpiston valve on its displacement being adapted to release a valvebetween the starting cylinders and said waste fluid chamber so that thestarting pistons return and permit said valves connecting the workingcylinders with said waste fluid chamber and said valves connecting samewith said accumulator to return to their contrary positions.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRITZ WOLFEI T SBERGER.

Witnesses: Lonrs VANDORN, OSCAR DEPNER.

